1. Field of the Invention
The present invention relates generally to cutting devices, and, more particularly, to a cutting torch aiming assembly for cutting holes of a predetermined size in metallic workpieces.
2. Description of the Prior Art
While not so limited, the present invention is particularly useful to ensure that metal products such as steel strip meet acceptable standards of quality and uniformity by periodic inspection of the metal during production of the product. In the past, inspection was made by the taking one or more small samples from the metal at various locations along the length thereof. Once removed from the metal strip, the samples may thereafter be analyzed to ensure that the quality and uniformity of the metal meets the required standards along the entire length of the workpiece.
In the existing art, when such a method of inspection is utilized, samples are most frequently taken from the metal strip through use of a punch and die setup. The punch and die allows holes to be punched through the metal strip thereby producing sample slugs which may be removed and analyzed. However, after repeated use of the punch and die, the punch and die becomes worn due to the hardness of the metal strip which may, for example, be a stainless steel alloy. After even a short period of operation, the punch and die are worn to such an extent that the strip of metal hangs onto the punch causing unnecessary delay time to the operation. Also, it is necessary to frequently replace the punch and die. Such replacement causes delay and downtime.
The punch and die are also frequently utilized to mark metal workpieces by cutting identification holes therethrough. Similarly, after repeated use of the punch and die setup, the punch and die becomes worn and must be replaced, once again causing delay and downtime.
Various devices and apparatus have been developed to cut holes in workpieces for many varying purposes. For example, U.S. Pat. No. 2,801,098 discloses a portable apparatus for burning circular holes in metal plate. The apparatus utilizes a conventional torch disposed in a support structure having a rotatably driven head member. Rotation of the head member about a vertical axis causes the torch to similarly rotate, thereby allowing the torch to burn a circular hole in the metal plate. Because the apparatus is portable, the torch may be transported and used at a job site making the apparatus of particular value to fabricators.
A punch press disclosed in U.S. Pat. No. 4,063,059 includes a plasma arc torch in addition to the conventional punch and die setup of a punch press. The punch and die setup is utilized to punch circular holes into a workpiece, while the plasma arc torch is utilized for cutting large and irregularly shaped holes into the workpiece. In a similar manner, a punch press disclosed in U.S. Pat. No. 4,201,905 includes a laser cutting head in addition to a conventional punch and die setup, such laser being utilized to mark a workpiece as well as to cut holes into the workpiece. Because of the small diameter of the laser beam, the laser may be utilized to bore small diameter openings into the workpiece. However, lasers are highly sensitive devices, and are frequently unusable in the high shock, vibration, and dust environment of a mill. Additionally, lasers of energies allowing the laser beam to cut holes into metal plate, such as stainless steel metal plate, are high cost devices.
Existing cutting devices utilizing plasma arc torches function to create either irregularly shaped, or large, circular holes in a workpiece. No prior art device can adequately control the aiming of a plasma arc torch to allow a hole of a small diameter to be created. What is needed, therefore, is an assembly to aim a plasma arc torch cutting device to cut holes of predetermined small diameters into a workpiece.
It is therefore the object of the present invention to provide a plasma arc torch apparatus allowing holes of small diameters to be cut into metallic workpieces.